To efficiently recover lithium from a lithium-containing metal oxide used in a positive electrode and the like of a discarded lithium ion secondary battery.
In a first step S101, the lithium-containing metal oxide, in which a transition metal oxide is combined with lithium, is mixed with an acid aqueous solution selected from diluted sulphuric acid and dilute nitric acid to produce a mixed liquid in which lithium is selectively leached. Then, in a second step S102, the mixed liquid is subjected to filtration to obtain a filtrate. Then, in a third step S103, pH of the filtrate is adjusted to 4.5 or more to produce an adjusted filtrate. Then, in a fourth step S104, the transition metal is removed from the adjusted filtrate by using a chelate adsorption resin to produce a removed filtrate. Then, in a fifth step S105, the removed filtrate is supplied with a carbonate ion to precipitate lithium carbonate from the removed filtrate and recover the lithium carbonate from the removed filtrate.
FURUYA TAKASHI
KUNIOKA TATSUYA
NAKAMURA JIRO
Shigeki Yamakawa
Yuzo Koike